Whangaehu River at 250 m from Confluence

The Whangaehu River catchment is located in the eastern Wairarapa and is a tributary of the Ruāmahanga River. The Whangaehu River upstream of Confluence site is located in the lower reaches of the river, and is accessed through private land only.

This site is monitored as part of a programme specifically designed to measure the health of rivers and streams in the Wellington Region. This involves monitoring of water quality (see the 'Scientific Indicators' tab below) as well as the aquatic invertebrate communities, i.e, the insects and bugs that live in the riverbed (see the 'Ecology' tab below).

Monitoring the different variables that affect water quality is carried out monthly. This involves the assessment of water clarity, nitrogen and phosphorus concentration, dissolved oxygen, pH and the concentration of the bacteria Escherichia coli (E. coli). The Macroinvertebrate Community Index (MCI) classifies the site based on the number of and different types of macroinvertebrates living there and is measured annually.

Water quality and macroinvertebrate health at this site is ok but bot great. This is a reflection of the surrounding land cover (which is dominated by pastoral land) and the fact that it is soft-bottomed (the riverbed is made up of silt and sand).

For more information on Greater Wellington Regional Council's environmental monitoring programmes, check out the latest water quality reports.

Water Quality

Water quality data for this site

Can I trust this data?

This dashboard shows information on the data collected by the regional councils for water quality indicators, analysed as state and trend.

State

State shows how the median of samples from this site compares to other sites.

This site is a Lowland Rural site. Currently showing the state of this site compared to:

The Cawthron Institute has worked alongside regional councils to verify the processes and methods used for data collection, laboratory analysis of samples collected and the statistical analysis and interpretation of the results presented.

If all Cawthron ticks are green, then you can trust this data. However, if one or more ticks are orange, then conclusions should be treated with some caution.

All samples were collected using approved field protocols and have been analysed in accredited laboratories. Therefore the data shown here has been collected and analysed following best practice.

State

All samples were collected using approved field protocols and have been analysed in accredited laboratories.

Trend - SAMPLING FREQUENCY

Samples are collected monthly at this site. Proposed national guidelines suggest monthly sampling is required for trend analysis. Therefore, any trends shown here are based on best practice in terms of sampling frequency.

Bacteria

E. coli

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State

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State

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NOF Band

N/A

NOF Band

Trend

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Sample history at this site

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E. coli samples for Whangaehu River at 250 m from Confluence

n/100ml

What is this graph showing me?

This graph is displaying E. coli concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard. This data is raw and has not had any methodology applied to it.

What do the icons mean?

For at least half the time, the estimated risk is <1 in 1000 (0.1% risk). The predicted average infection risk is 1%*.

B

For at least half the time, the estimated risk is <1 in 1000 (0.1% risk). The predicted average infection risk is 2%*.

C

For at least half the time, the estimated risk is <1 in 1000 (0.1% risk). The predicted average infection risk is 3%*.

D

20-30% of the time, the estimated risk is >=50 in 1000 (>5% risk). The predicted average infection risk is >3%*.

E

For more than 30% of the time, the estimated risk is >=50 in 1000 (>5% risk). The predicted average infection risk is >7%*.

* The predicted average infection risk is the overall average infection to swimmers based on a random exposure on a random day,
ignoring any possibility of not swimming during high flows or when a surveillance advisory is in place (assuming that the
E. coli
concentration follows a lognormal distribution). Actual risk will generally be less if a person does not swim during high flows.

Clarity

State

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Trend

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Sample history at this site

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Black Disc samples for Whangaehu River at 250 m from Confluence

metres

What is this graph showing me?

This graph is displaying Black Disc readings over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard. This data is raw and has not had any methodology applied to it.

State

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Trend

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Sample history at this site

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Turbidity samples for Whangaehu River at 250 m from Confluence

NTU

What is this graph showing me?

This graph is displaying Turbidity levels over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard. This data is raw and has not had any methodology applied to it.

Nitrogen

State

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Trend

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Sample history at this site

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Total Nitrogen samples for Whangaehu River at 250 m from Confluence

g/m3

What is this graph showing me?

This graph is displaying Total Nitrogen concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard. This data is raw and has not had any methodology applied to it.

State

State

Trend

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Sample history at this site

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Total Oxidised Nitrogen samples for Whangaehu River at 250 m from Confluence

g/m3

What is this graph showing me?

This graph is displaying Total Oxidised Nitrogen concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard. This data is raw and has not had any methodology applied to it.

Water quality is not considered suitable for the designated use.Impacts on growth of multiple species, and effects starts approaching acute impact level (i.e. risk of death) for sensitive species at higher concentrations (>20 mg/L).

State

State

Trend

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Sample history at this site

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Ammoniacal Nitrogen samples for Whangaehu River at 250 m from Confluence

g/m3

What is this graph showing me?

This graph is displaying Ammoniacal Nitrogen concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard. This data is raw and has not had any methodology applied to it.

Phosphorus

State

Trend

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Sample history at this site

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Dissolved Reactive Phosphorus samples for Whangaehu River at 250 m from Confluence

g/m3

What is this graph showing me?

This graph is displaying Dissolved Reactive Phosphorus concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard. This data is raw and has not had any methodology applied to it.

Taxonomic richness is the number of different taxa present in an ecological community identified to the best possible level.

Taxa richness history at this site

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Taxa richness for Whangaehu River at 250 m from Confluence

Number of taxa

Percent EPT richness

The median of the last 5 years of data

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EPT are macroinvertebrates that are sensitive to water pollution. These are Ephemeroptera (mayfly), Plecoptera (stonefly) and Trichoptera (caddisfly).

EPT history at this site

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Percent EPT richness for Whangaehu River at 250 m from Confluence

EPT %

Can I trust this data?

The Cawthron Institute has worked alongside regional councils to verify the processes and methods used for macroinvertebrate data collection, processing of the data in the laboratory, quality control in the field and laboratory and the statistical analysis and interpretation of the results presented.

Macroinvertebrates are sampled at this site as part of council's stream health monitoring programme, as recommended by proposed national guidelines.

Sampling - Frequency

Macroinvertebrate sampling is done annually or more frequently at this site as recommended by proposed national guidelines. Therefore, data shown here follow current best practice guidelines.

Sampling - Protocols

This site is a hard-bottomed site and appropriate sampling protocols have been applied. Data shown here have been collected using current best-practice.

Sampling - Habitat

Macroinvertebrate sampling is done in riffle habitat at this site. Data shown here are therefore following best practice.

Sampling - Stand-down period

This council does not collect any macroinvertebrate samples for up to two weeks after a flood greater than three times the median flow as recommended by proposed national guidelines. Therefore, data collected at this site is following best practice.

Processing - Protocol

Samples at this site have been processed following sampling potocols P2 or P3 and data have been processed following best practice.

Quality Control - Field

Field data collected at this site had no quality control applied to it.

Quality Control - Lab

Data processed at this site has had one of the three Laboratory Quality Control Protocols (i.e., QC1, QC2,Q C3) applied. Data shown here is more robust than data with no laboratory QC applied.